Alcatel Carrier Internetworking Solutions Switch/Router ユーザーズマニュアル

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Setting Up IP Routing on the Switch
Page 25-4
Setting Up IP Routing on the Switch
IP routing is enabled on a per-port basis by creating a virtual IP router port for a group/
VLAN
The switch does not do any routing unless the virtual router port has IP routing enabled 
(routing is enabled by default). The steps for setting up IP routing on the switch are given 
here:
Step 1. Configuring a Virtual Router Port
A virtual router port may be created when you set up or modify a group/
VLAN
 through the 
crgp
 command or 
modvl
 command described in Chapter 19, “Managing Groups and Virtual 
Ports.” To create a virtual router port, enable IP routing and specify an IP address for the 
router port. 
When routing is enabled on the port, the switch creates routing tables and address transla-
tion tables so it knows how to forward traffic. The switch keeps track of router ports and any 
other routers in the network. The switch uses the Address Resolution Protocol (
ARP
) to match 
IP addresses with 
MAC
 addresses. It uses routing protocols, such as the Routing Information 
Protocol (
RIP
), to determine the best path for forwarding traffic. (Other routing protocols are 
available in the Advanced Routing software package.) It also periodically sends/receives rout-
ing messages to/from other routers to keep its routing tables updated. 
♦ Important Note 
When Spanning Tree and IP routing are both enabled, 
packets are not forwarded unless the Spanning Tree 
Status for the port to which packets are to be 
forwarded has progressed from Listening to Learning to 
Forwarding. For example, if IP is enabled on 
VLAN
 42 
that has ports 1/1-3 attached to it and you want to 
forward to a host from port 1/2. Use the 
vi 1/2
 
command to determine if the Spanning Tree Protocol 
has entered the Forwarding state for that port. 
Step 2. Configuring Optional IP Routing Parameters
Optional configuration for IP routing includes the following:
• Static routes. These are routes that are manually added to the routing table and may be 
used rather than dynamic routes (which are learned through routing protocols like 
RIP
).
RIP
 filters. Controls the operation of 
RIP
 by minimizing the number of entries that will be 
added to the routing table.
Static routes and 
RIP
 filters are described in this chapter. This chapter also describes how to 
view various IP statistics as well as the routing table. It includes information about how to 
ping another IP host in the network, how to telnet to a remote system, and how to trace an IP 
route.